Expanding tap.



No. 804,928. PATENTED NOV. 21, 1905.

G. H. BURLEY. I

EXPANDING TAP.

APPLICATION FILED APILSO, 1904.

Inve

Attorneys GEORGE H. BURLEY, OF TYRONE, PENNSYLVANIA.

EXPANDING TAP.

Specification of Letters Patent.

Patented Nov. 21, 1905.

Application filed April 30, 1904:. Serial No. 205,809.

To all whom it may concern.- 7

Be it known that I, GEORGE H. BURLEY,

a citizen of the United States, residing at Tyrone, in the county of Blair and State of Pennsylvania, have invented a new and useful Expanding Tap, of which the following is a specification.

This invention relates to screw-cutting implements or taps for cutting interior threads, and has for its object to provide for conveniently adjusting the set of the cutters or bits so as to fit openings of difierent sizes.

Another object is to provide for adjusting the tool so as to collapse when a predetermined length of thread has been cut.

l/Vith these and other objects in view the present invention consists in the combination and arrangement of parts, as will be herein after more fully described, shown in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that changes in the form, proportion, size, and minor details may be made within the scope of the claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings, Figure 1 is a longitudinal sectional view of the present tool with the cutters or bits in their retracted position. Fig. 2 is a similar view with the cutters or bits projected in position for use.

Like characters of reference designate corresponding parts in each and every figure of the drawings. i

As in my former tool, the present tool embodies an open-ended tubular stock 1, which is provided atits forward end with a plurality of radial openings 2 for the reception of the usual form of bits or cutters 3. The forward end of the stock is internally threaded for the reception of a removable closure-plug, (not shown,) which may or may not be used, as desired.

Working endwise within the stock is a plunger 1, the rear portion of which is embraced by a helical spring 5, having its rear end bearing against an annular shoulder or collar 6, preferably in the form of a nut, with its forward end bearing against an inner annular flange 7 upon the stock, wherebythe plunger is normally and yieldably held at its inner limit. The forward end of the body of the plunger is terminated short of the rear ends of the openings 2 and is provided with a beveled tubular head 8, which is separate therefrom and connected thereto through the medium of a stem 9, the body portion of which is cylindrical in shape, so as to slide endwise and also rotate within the head, the inner end portion of the stem being provided with reversely-disposed screw-threaded portions 10 and 11, fitted within corresponding screw-threaded sockets in the head and the body of the plunger. The outer end of the stem is accessible from the open front of the stock and is provided with a groove 12 to form a screw-driver seat, so that by rotating the stem the headmay be adjusted toward and away from thebody of the plunger, thereby to regulate the outward adjustment of the bits or cutters 3 when the plunger has been moved to its outer limit. By this-means the diameter of the thread-cutting portion of the tool may be readily adjusted without taking the tool apart, and therefore said tool may be quickly adjusted to fit any opening within the capacity of the tool.

To hold the plunger at its forward limit against the tension of the spring 5, I employ a pair of dogs 13, arranged side by side within a transverse opening 14 in the body of the plunger, each dog having a lateral arm 15 projected outwardly beyond the plunger and entering a slot 16 in the stock, the extremity of the arm being projected externally of the s ot.

Mounted to slide longitudinally upon the exterior of the stock is an adjusting-slide in the form of a collar made up of two parts 17 and 18, the inner abutting ends of which are provided with registered recesses 19 and 20, respectively, to receive the projected end of the arms 15 of the dogs, so that by sliding the two-part collar upon the stock the dogs may be pivotally turned upon their common pivotal support 21 to expand or separate the dogs, so as to bring their free ends into engagement with the backs of the slots 16, and thereby lock the plunger at its forward limit. By drawing the slide rearwardly the dogs will of course be swung inwardly out of engagement with the rear ends of the slots 16, thereby freeing the plunger from the stock and permitting the spring 5 to automatically return the plunger to its normal position, thereby withdrawing the head 8 from the bits or cutters 3 and permitting the latter to move IIO The recesses 19 and 20 are formed in external annular enlargements of the collar-sections, and these enlargements are externally screw-threaded, so as to receive an internallyscrew-threaded ring or band 22, between the rear portion of which and the rear collar-section 18 is fitted an eXternally-screw-threaded flanged nut 23, which engages the internal screw-threads of the ring. The forward portion of the ring is internally smooth, and a front internally-flanged nut 24 is fitted within this smooth portion of the ring and engages an externally-screW-threaded portion of the front collar-section 17. This front nut'24 is normally projected in front of the rear ends of the slots 2, so as to embrace the rear ends of the bits or cutters, and thereby prevent the bits from falling out of the slots 2 when the tool is not engaged with the work.

The function of the ring 22 is to effect an automatic collapsing of the bits or cutters when the screw-threads have been cut for a predetermined length, and this is accomplished by turning the ring so as to project the same in advance of the nut 24, and thereby form a stop-shoulder which is designed to strike the outer face of the piece of work 25 in which the cutters are operating, whereby any further inward movement of the stock will result in the inward swinging or drawing together of the dogs until they disengage from the stock, and the plunger will then be automatically drawn away from the bits or cutters by the spring 5 and the cutters will move inwardly out of engagement with the threads which have been cut, thus permitting of the tool being withdrawn endwise without requiring rotation thereof.

It will be noted that the opening in the ring 24 is flared at its outer end, so as to produce an internal beveled surface for contact by the inner ends of the bits when the ring 24 is projected to overlap the inner ends of the slots 2, said beveled surface forming a stop to adjustably limit outward movement of the bits.

Having thus described the construction and operation of my invention, what I claim as new, and desire to secure by Letters Patent, 1s

1. In an expanding screw-tap, the combination of an open-ended tubular stock, a radially-adjustable bit thereon, a non-rotatable plunger working within the stock, manuallycontrolled means to shift the plunger and lock the same against endwise movement, a beveled head separate fromthe plunger and in frictional engagement with the bit, and an ad justing screw-threaded pin piercing the head and engaging the plunger with its outer end accessible through the adjacent open end of the stock to adjust the head longitudinally of the plunger and feed the bit radially without additional movement of the plunger.

2. In an expanding screw-tap, the combination of an open-ended tubular stock, a radially-adjustable bit carried thereby, a non-rotatable plunger working within the stock and provided in its forward end with a threaded socket, manually-controlled means to shift the plunger and lock the same against endwise movement, a beveled head cooperating with the bit to force the same radially outward and provided with an open-ended longitudinal bore having a screw-threaded portion, and an adjusting-stem fitted in the bore of the head and intermediately threaded to engage the threads of the bore and having its inner terminal threaded reversely from the intermediate threaded portion and engaging the threaded socket in the end of the plunger, the outer end of the stem having a head which is accessible through the adjacent open end of the stock to rotate the stem and adjust the head to feed the bit radially when the parts are assembled without additional movement of the plunger.

3. An expanding screw-tap comprising a stock, a radially-adjustable bit carried thereby, bit-adjusting means, and trip means including a rotatable ring having an adjustable threaded connection with the bit-adjusting means to set the ring to different predeter.

mined positions for contact with the work to release the bit-adjusting means.

4:. An expanding screw-tap comprising a stock, a radially-adjustable bit, bit-adjusting means, a controlling-ring slidably embracing the stock and connected to the bit-adjusting means and also provided with a screw-threaded portion, and a rotatable trip-ring having a screw-threaded part adjustably embracing the screw-threaded part of the controllingring and capable of being set thereon for contact with the work to actuate the sliding ring and release the bit.

5. An expanding screw-tap comprising a tubular stock, a radially-adjustable bit, bitadjusting means within the stock and having a portion projected through an opening therein, a controlling-ring slidably embracing the stock and connected to theprojected portion of the bit-adjusting means, an intermediate portion of the slide having an annular enlargement which is screw-threaded, a threaded rotatable trip-ring adjustably engaging the screW-threaded part of the slidable ring and capable of being set thereon for contact with the work, and a nut embracing the slidable ring and engaging the screw-threaded part of the trip-ring.

6. An adjusting screw-tap comprising a stock, a radially-adjustable bit, bit-adjusting means, and a controlling-slide embracing the stock and connected to the bit-adj usting means, one end of the slide being formed to embrace the adjacent end of the bit.

7. An expanding screw-tap comprising a stock, a radially-adjustable bit, bit-adjusting means, a slide embracing the stock and having a portion formed to embrace the adjacent end of the bit, and a trip adjustably carried by the slide and capable of being set for contact With the work and connected With the bit-adjusting means to release the same and the bit when the trip contacts With the work.

8. An expanding screw-tap comprising a tubular stock having a radial opening, a radially-adjustable bit working in the opening, bit-adjusting means Working Within the stock and having a portion projected externally through the opening in the stock, a tubular slide embracing the stock and connected to the projected portion of the bit-adjusting means, said slide having an intermediate annular enlargement which is screw-threaded, the external portion of the slide in rear of the enlargement being smooth, and the external portion in front of the enlargementl being screw-threaded, a trip-ring having an internally-screw-threaded portion adjustably fitting the screw-threaded enlargement of the slide, a flanged nut embracing the smooth rear portion of the slide and engaging the screw-threaded portion of the trip-ring, and a nut adjustably embracing the front screwthreaded part of the slide and having an inner annular flange to embrace the rear end of the bit.

In testimony that I claim the foregoing as my oWn I have hereto aflixed my signature in the presence of two Witnesses.

GEORGE H. BURLEY.

Witnesses:

P. W. SMITH, TIP SILINGER. 

